Container initialization in C++98

Question

I have to construct an ordered container (which must be iterable) with the following rule:

If the condition is true, the container is {1,0}, else it's {0,1}

I have the following code, but I don't find it "elegant":

   vector<int> orderedSides;
   if (condition) 
   {
       orderedSides.push_back(1);
       orderedSides.push_back(0);
   }
   else            
   {
       orderedSides.push_back(0);
       orderedSides.push_back(1);
   }

Is there a better way to do this (from concision and performance point of view)?

Answer 1

You might implement something like this:

vector<int> orderedSides(2, 0);
(condition ? orderedSides.front() : orderedSides.back()) = 1;

which is a little bit shorter than explicit if clauses.

As @Deduplicator mentioned below, we might rewrite the second line in a more concise way:

orderedSides[!condition] = 1;

Answer 2

vector<int> orderedSides;
orderedSides.push_back(condition ? 1 : 0);
orderedSides.push_back(condition ? 0 : 1);

I don't think it's more performant but I find it more elegant.

Answer 3

You could compromise between efficiency and avoiding repetition, initialise the first with the condition and the second from the first.

vector<int> orderedSides(1, bool(condition)) ;
orderedSides.push_back(!orderedSides.back());